Deep-drawing press

ABSTRACT

The invention relates to a deep-drawing press with a multi-stage die set comprising a plurality of dies arranged in sequence and punches moving telescopically inside each other, each of which, after a given length of travel, remains at an associated die which serves as a hold-down ring; the punches are powered by a plurality of coaxial annular pistons.

[ 51 Dec. 26, 1972 United States Patent Berg [54] DEEP-DRAWING PRESS[72] Inventor: Gunter Rudolf Berg, l-lopfengarten 2, 33 Braunschweig,Germany 1/1943 Germany................................72/349 223,43010/1924 GreatBritain..........................72/349 2 J2 w D9 0 N L o.mp FA .1] 21 22 Primary Examiner-Richard J. Herbst Attorney-Norman S.Blodgett Foreign Application Priority Data ABSTRACT Dec. 10, 1970Germany....................

$3 a uhS w%n v m w wmm moehh P do w aPn a .mmm r mnm al fi rp a A m ,d Pm e ebwa unman-mu dwn o afiuffi 0.0.0 mmmm m n ate m: re m.m nil" o W me m flue C a.m m d v .l m e omm h f Tmm.mo 988 4R6 B2 22 .d 1 3 "M5 m.4m9 4 3 "UN mm7 M ""m t n :I m"m C "m S u. e n c m m m .mnm r. m m R ""8e 8 m S .M mh UIF II] I 2 00 6 555 5 [rl[ UNITED STATES PATENTS v ahold-down ring; the punches-are powered by a plurality of coaxialannular pistons.

3,470,725 l0/l969 Brown et a1. 2,804,848 9/1957 OFarrell eta1........................91I168 3 Claims, 7 Drawing Figures PATENTEDB BM 3 707 086 sum 1 or 4 l L J INVENTORZ ll Gum-YER BERG Aamim PATENTED m26 1972 sum 3 OF 4 mm t PATENTED DEC 2 6 I972 SHEET l 0F 4 DEEP-DRAWINGPRESS BACKGROUND OF THE INVENTION With prior art deep-drawing presses ofthis type, the control means is generally a complicated unit, which isnot part of the deep-drawing press and is separately installed outsidethe press. Irrespective of whether control takes place by a program orsequence control system, this prior art arrangement entails dead timesthat adversely affect the operational sequence and cycle times of thedeep-drawing press. With a deepdrawing press of this type, if thepunches, after a prescribed length of travel, are to remain effective atan associated die acting as hold-down ring, additional dead times areentailed, so that the control means is technically more complicated andmore costly as well as being prone to trouble. These and otherdifficulties experienced with the prior art devices have been obviatedin a novel manner by the present invention.

It is, therefore, an outstanding object of the invention to provide adeep-drawing press having a simplified control means incorporated as anintegral component. In so doing, unproductive times entailed with priorart versions are reduced, including the times for those control dutiesto ensure that the punches, after a prescribed length of travel, remaineffective on an associated die as a hold-down ring.

Another object of this invention is the provision of a deep-drawingpress that costs less to construct and constitutes an improvement withrespect to operational sequence and cycle times.

With these and other objects in view, as will be apparent to thoseskilled in the art, the invention resides in the combination of partsset forth in the specification and covered by the claims appendedhereto.

SUMMARY OF THE INVENTION In general, the invention consists of adeep-drawing press having a control means comprising plunger-typevalves, positively connected to all but the final annular piston, withcontrol members for conducting the pressure medium to the piston endareas. The said plunger type valves act as a sequence control withmembers controlling in succession the flow of pressure medium topressure chambers in front of the second to the final annular piston. Atthe backs of the first to the penultimate annular pistons, differentialend areas are formed. After adjacent annular pistons are mutuallysupported by the stop rings in the inward position, the pressure mediumon the one hand flows in front of the end areas of the operating pistonsand, on the other hand, to the differential piston area of the first tothe penultimate annular pistons, thereby determining the hold-downforce, the differential force acting on the respective annular pistons.I

BRIEF DESCRIPTION OF THE DRAWINGS The character of the invention,however, may be best understood by reference to one of its structuralforms, as illustrated by the accompanying drawings, in which:

FIG. 1 is a side view partly in section of a deep-drawing pressincorporating the principles of the present invention,

FIG. 2 is a somewhat-enlarged view of a portion of the press,

FIG. 3 is a sectional view of the press taken on the line III-III ofFIG. 2,

FIG. 4 is a sectional view of the press taken on the line IV-lV of FIG.2,

FIG. 5 is a sectional view of the press taken on the line V-V of FIG. 2,

FIG. 6 is a sectional view taken on the line Vl-VI of FIG. 5, and

FIG. 7 is a sectional view taken on the line VII-VII of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT According to a preferredembodiment of theinvention, the control elements of the plunger typevalves taken the form of holes, edges and, possibly, ducts inacylindrical shell. Moreover, annular spaces are provided betweenadjacent plunger type valves to conduct the pressure medium to theassociated annular pistons.

According to another embodiment, the differential piston areas arecomprised of the supporting surfaces covered by the stop rings when theannular pistons are in the inward position, and of the piston end areasadjoining thepressure chambers.

It goes without saying, that the deep-drawing press, according to theinvention, exhibits a housing acting as cylinder for the first annularpiston and that a stub is provided for connection to the pressure mediumsupply. Said housing is also extended beyond the plunger type valves andprovided with control elements in the fonn ofedges that cooperate withthe plunger type valve of the first annular piston. There is no need fora separate plunger type valve to be connected to the final annularpiston, as said final piston is the last to receive the pressure mediumand thus concludes the work cycle of said deep-drawing press.

In other branches of technology, actuators are employed that feature aplurality of coaxial annular pistons which automatic control themselves.So far, however, they have had no influence on the design ofdeep-drawing presses of the type conforming to the invention. In theircase, there is, in fact, no problem of maintaining a given degree ofpressure exerted by an annular piston in the outward position, forperforming a given function in the case of this invention, the holdingdown of the blank.

' All spaces of the deep-drawing press, conforming to the invention,filled or to be filled with a pressure medium must be suitably sealed.For this purpose, the free end of the plunger type valve connected tothe annular piston should be provided with packings flush with thecontrol edges. Said packings together with the control edges seal offthe annular spaces between adjacent plunger type valves. It goes withoutsaying that there is also a packing between the plunger type valve ofthe second annular piston and the steel edge of the housing. The annularpistons of the deep-drawing press disclosed by the invention areprovided with packings in a manner known per hold-down The advantageafforded by the invention are, above all, that the control means of saiddeep-drawing press is incorporated as an integral component of the pressand the possibility of controlling the travel of the individual annularpistons in relation to function, without complicated and costlymechanisms. At the same time,

dead times are obviated. Moreover, the design of the annular pistonswith stop rings on the end areas and the provision of differentialpiston surfaces, itself a significant feature of the invention, ensuresthat the individual operations proceed in a definite sequence. This notonly enables the individual annular pistons to perform their strokesbut, at the end" thereof, to exert a hold-down force.

' The press disclosed by the invention is suitable not only for the deepdrawing of plate and sheet, but for sizing deep-drawn components. Whenan article is sized subsequent to deep drawing, it is forced through adie to produce a given external dimension, the wall thickness beingreduced by the action in cooperation with the mating punch.

. The deep-drawing press depicted in the drawings has a multi-stage dieset comprising four successive dies 1,

'2, 3, and 4, and four telescopically-arranged punches 5,

6, 7, and 8 nesting within each other, the first three of said punches5, 6, and 7 at the end of their predetermined stroke continuing to" actas holddowns in cooperation with an associated die. Punches 5, 6, 7, and8 are surrounded by a main hold-down. Drive to these punches 5, 6, 7,and 8 is by four coaxially arranged annular pistons 10, 11, 12, and 13attached to said punches and moved by a pressure medium. The four saidannular pistons 10, 11, 12, and 13, with their four associated pistonrods 14, l5, l6, and 17, are telescopically arranged within each otherand accommodated in a housing 18 provided with a stub 19 for connectingthe pressure medium supply line. Said housing 18 is designed as acylinder for the first annular piston and piston rod 14 of the firstannular piston 10 serves as'cylinder for the second annular piston 11,piston rod 15 of the second annular piston 11 acting as cylinder for thethird annular piston 12, and piston rod 16 of the third annular piston12 as cylinder for the fourth annular piston 13.

The deep-drawing press is provided with a control means which enablesthe annular pistons 10, 11, 12, and 13 to be moved outwards 'insequence, starting with the outermost and ending with the innermostthereof. Attached to the second and third annular pistons 11 and 12 andcoaxial therewith, the control means has plunger type valves 20 and 21with control elements for directing the pressure medium to annularpistons 11, 12, and 13. Said plunger type valves 20 and 21 are operatedsuccessively in the manner of a sequence control, thereby controllingthe flow of pressure medium to the second, third, and fourth annularpistons 11, 12, and 13. For control elements the plunger type valves 20and 21 have ports 22, 23, and 24 and edge 25. Plunger type valve 20connected to the second annular piston 11 is additionally provided withacontrol duct 26 in its cylindrical shell. Said duct communicates withport 22, thereby enabling the flow of pressure medium to the second andthird annular pistons 11 and 12 to be controlled in sequence by saidplunger type valve 20. Housing 18, extending beyond plunger type valves20 and 21, also exhibits a control edge 27, which cooperates with theports 22 and cooperates of plunger type valve 20 connected to the secondannular piston '11. 'Annular spaces 28 and 29, between adjacent plungertype valves 20 and 21, are additionally provided to conduct pressuremedium to annular pistons 11, 12, and 13. In front of annular pistons11, 12, and 13, that is to say, at the end to which pressure medium mustflow to effect'outward displacement, are provided pressure chambers 30,31, and 32communicating with annular spaces 28 and 29 and control duct26, respectively.

1n the drawings of the deep-drawing press, the annular pistons 10, 11,12, and 13 are shown in their inward position. Said annular pistons 10,11, 12, and 13 are supported one against the other by stop rings 34,clear of pressure chambers 30, 31,- and 32. During the out;

ward stroke, the first annular piston 10 carries forward the secondannular piston 11 by engaging the stop-ring mounted on said secondannular piston, and when the second annular piston 11 is displaced, itcarries along the third and the third annular piston 12 carries alongthe fourth annular piston 13., Differential piston surfaces 35 areformed at the back of the four annular plungers 10, ll, 12, and 13.After the stop rings 34 have lifted, pressure medium flows both in frontof the working faces 33 of the annular pistons and at the back of thedifferential faces 35 of annular pistons 10, 11, and 12, thedifferential force thereby generated being exerted by the respectiveannular pistons 10, 11, and 12 forholding down. The differential pistonsurfaces 35 are comprised of the support surfaces 41 covered by the stoprings 34 when the annular pistons 10, 11, 12, and 13 are in the inwardposition, pressure chambers 30, 31, and 32 and annular spaces 28 and 29or the piston areas 42 flanking the control duct 26. (FIGS. 3a and 3b).

All spaces of the illustrated deep-drawing press that are filled or tobe filled with pressure medium are sealed in a manner known per se.Plunger type valves 20 and 21 connected'to'annular pistons 11 and 12 areprovided on the inside of their free end with packings 36. Said packings36 seal off the annular spaces 28 and 29 between the adjacent plungertype valves 20 and 21. A packing 37 is also fitted at'the control edge27 of housing 18 between said housing and the plunger type valve 20 ofthe second annular piston 1 1.

On the deep-drawing press disclosed by the invention a receiving piston38 of fixed arrangement cooperates with the fourth annular piston 13 andis coaxial with the other annular pistons 10, 11, and 12. Connected tosaid receiving piston 38 is a piston rod 39 provided with an orifice 40for the pressure medium supply. Piston rod 17 of the fourth annularpiston 13 serves as cylinder for receiving piston 38, said piston rod 17enclosing the piston rod 39 of said receiving piston 38.

The mode of operation of the deep-drawing press disclosed by theinvention is as follows:

Pressure medium flows to the first annular piston 10 through the stubconnection 19 of housing 18. Said pressure medium causes the firstannular piston 10 to move outward and through stop rings'34 the otherannular pistons 11, 12, and 13 are entrained. Just before the firstannular piston 10 completes its stroke, that is to say, immediatelyprior to the punch 5 attached to said first annular piston 10 makingcontact with its associated die 2, the first orifice 22'of the plungertype valve 20 connected to the second annular piston 11 is cleared bythe control edge 27 on the extended housing 18, thereby permitting thepressure medium to flow through duct 26 in the cylindrical valve shellto pressure space 30. Under the influence of the pressure medium, thesecond annular piston 11 starts its outward movement. As a result, thepressure medium flows up against the differential surface 35 of thefirst annular piston thereby partly balancing out the force acting onsaid annular piston 10 and slowing down its outward movement, and afterthe punch 5 has made contact with its associated die 2 the differentialforce acts as a hold-down force upon the annular piston 10. When thesecond annular piston 11 has completed its drawing stoke, the controledge 27 on housing 18 clears the second orifice 23 in the plunger typevalve connected to the second annular piston 11, as a result of whichthe pressure medium flows into the pressure space 31 through the annularspace 28 between the two plunger type, valves 20 and 21 connected to thesecond and third annular pistons 11 and 12. The third annular piston 12starts to move outwardly and carries along the fourth annular piston 13.After the outward movement of the second annular piston 11 has sloweddown and the punch 6 is in contact with the die 3, the pressure actingon said piston 11 through the pressure medium ahead of the face end 33and differential surface 35 serves as a hold-down force. Shortly beforethe third annular piston 12 completes its drawing movement, the orifice24 of plunger type valve 21 connected to said third annular piston 12 ispassed by the control edge of the plunger type valve 20 connected to thesecond annular piston 11. As a result, the pressure medium is able toflow through orifice 24 and annular space 29 between the plunger typevalve 21 connected to the third annular piston 12 and the piston rod 39of receiving piston 38 to pressure chamber 32 ahead of the fourthannular piston. This causes the fourth annular piston 13 to start itsoutward movement and, at the same time, the hold-down force acts uponthe annular piston 12.

When the deep-drawing operation is concluded, the return travel of theannular pistons 10, 11, 12, and 13 is effected by permitting thepressure medium to flow back into a reservoir, not illustrated, througha pipe connected with the stub 19 on housing 18. The pressure mediumflows through the piston rod 39 of receiving piston 38 and port 40,thereby acting on the stationary receiving piston 38 and the fourthannular piston 13, which begins its inward movement, thereby initiatingthe return travel of the other annular pistons 12, 11, and 10 to theirrest position. In so doing, annular pistons 13, 12, 11, and 10 supporteach other through their stop rings 34. The pressure medium therebyexpelled flows through passages 22, 23, and 24 to the plunger typevalves 20 and 21 and through port 19 to discharge into the reservoir. Nodifficulties will be encountered in that ports 22, 23, and 24 arecovered by the associated control edges 25 and 27 only when there is noflow of pressure medium.

1. A deep-drawing press with a multi-state die set consisting of aplurality of successively arranged dies and punches movingtelescopically within each other,-

after performing a predetermined drawing movement the punches exertpressure on an associated die acting as a hold-down ring, a driveconsisting of the same number of coaxial annular pistons attached tosaid punches, the pistons being subjected to the influence of a pressuremedium, and a control means that permits all of the said annular pistonsto be moved axially in sequence, from the outside inward,

characterized by the fact that the control means comprises coaxialplunger. type valves (20 and 21) integral with the first, second andpenultimate annular pistons (10, 11 and 12), with elements for the flowof pressure medium to the end faces of said annular pistons, saidplunger type valves (20 and 21) having elements acting in successioninthe manner of a sequence control to control the flow of pressure mediumto pressure chambers (30, 31 and 32) in front of the second andpenultimate annular pistons, the backs of the first to penultimateannular pistons (10, 11 and 12) are provided with differential pistonsurfaces (35) so that, after the lifting of stop rings (34), throughwhich adjacent annular pistons engage each other in the inward position,said pressure medium flows on the one hand to the working face and onthe other hand to the differential piston surface (35) of the pistons,thereby determining the differential pressure exerted by the respectiveannular pistons.

2. A deep-drawing press as set forth in claim 1,

characterized by the fact that the control elements of the plunger typevalves 20 and 21) take the form of passages (22, 23 and 24) and edges(25) in the cylindrical valve shell and that annular spaces (28 and 29)are provided between adjacent plunger type valves (20 and 21) fordirecting the flow of pressure medium to the associated annular pistons(11,12 and 13).

3. A deep-drawing press as set forth in claim 1,

characterized by the fact that the differential piston surface (35)consists of the supporting surfaces (41) engaged by the stop rings (34)in the inward position of the annular pistons (10, ll, 12 and 13) andthe piston areas (42) flanking the pressure chambers (30, 31 and 32).

1. A deep-drawing press with a multi-state die set consisting of aplurality of successively arranged dies and punches movingtelescopically within each other, after performing a predetermineddrawing movement the punches exert pressure on an associated die actingas a hold-down ring, a drive consisting of the same number of coaxialannular pistons attached to said punches, the pistons being subjected tothe influence of a pressure medium, and a control means that permits allof the said annular pistons to be moved axially in sequence, from theoutside inward, characterized by the fact that the control meanscomprises coaxial plunger type valves (20 and 21) integral with thefirst, second and penultimate annular pistons (10, 11 and 12), withelements for the flow of pressure medium to the end faces of saidannular pistons, said plunger type valves (20 and 21) having elementsacting in succession in the manner of a sequence control to control theflow of pressure medium to pressure chambers (30, 31 and 32) in front ofthe second and penultimate annular pistons, the backs of the first topenultimate annular pistons (10, 11 and 12) are provided withdifferential piston surfaces (35) so that, after the lifting of stoprings (34), through which adjacent annular pistons engage each other inthe inward position, said pressure medium flows on the one hand to theworking face and on the other hand to the differential piston surface(35) of the pistons, thereby determining the differential pressureexerted by the respective annular pistons.
 2. A deep-drawing press asset forth in claim 1, characterized by the fact that the controlelements of the plunger type valves (20 and 21) take the form ofpassages (22, 23 and 24) and edges (25) in the cylindrical valve shelland that annular spaces (28 and 29) are provided between adjacentplunger type valves (20 and 21) for directing the flow of pressuremedium to the associated annular pistons (11, 12 and 13).
 3. Adeep-drawing press as set forth in claim 1, characterized by the factthat the differential piston surface (35) consists of the supportingsurfaces (41) engaged by the stop rings (34) in the inward position ofthe annular pistons (10, 11, 12 and 13) and the piston areas (42)flanking the pressure chambers (30, 31 and 32).